While the main research interest of this laboratory continues to be focused on the new human papovaviruses, other members of the papovaviridae family are being investigated. Attempts are being made, for example, to propagate the human wart virus in tissue culture. JC virus has been successfully grown in human amnion cells through 2 passages. Although the yields are low, this is the first time this virus has been grown in cells other than human fetal glial cells. Studies on the characterization of K virus, a mouse papovavirus, and its relation to polyoma virus have revealed that the 2 mouse papovaviruses do not share common structural or T-antigens, and their DNAs have no detectable common sequences as determined by standard nucleic acid hybridization methods. However, in confirmation of the results of Shah, et al, antiserum prepared against disrupted virions of K virus or polyoma virus cross-react against other members of the polyoma virus subgroup. BIBLIOGRAPHIC REFERENCES: Howley, P.M. Khoury, G., Takemoto, K.K., and Martin, M.A.: Polynucleotide sequences common to the genomes of simian virus 40 and the human papovaviruses JC and BK. Virology 73: 303-307, 1976. Mason, D.H., Jr. and Takemoto, K.K.: Transformation of rabbit kidney by BKV(MM) human papovavirus. Int. J. Cancer 19: 391-395, 1977.